| 摘要 |
PURPOSE:To transmit the required quantity of light irrespective of astigmatic difference by using a cylindrical lens which has refracting power within the plane parallel to an objective lens focusing at the beam west position within the plane perpendicular to the junction face with a semiconductor laser. CONSTITUTION:The luminous fouxes radiated from the beam west position 6a within the plane perpendicular to the junction face of a laser 7 and the beam west position 6b within the plane parallel to the junction face are recieved in an objective lens 8 and the luminous fluxes out from this are paralleled with a cylindrical lens system 9. The lens system 9 has refractive power only in the direction parallel to the junction face of the laser 7 and magnifies the luminous flux diameter in the direction parallel to the junction face. The focus of the lens 8 aligns to the beam west position in the direction perpendicular to the junction face of the laser 7 and the codmbined focus of the lens 8 and lens system 9 within the plane parallel to the junction face is put in the position within a range of diffraction limit with respect to the beam west position within the plane parallel to the junction face. Thereby, the necessary quantity of light may be transmitted onto a photosensitive medium irrespective of astigmatic difference.
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